PROJECT SUMMARY Dr. Lipson's career objective is to become a leading mental health disparities researcher, contributing novel evidence about structural determinants of disparities in adolescent and young adult populations, specifically for transgender and gender nonconforming (TGNC) individuals (those who have a gender identity that differs from assigned sex at birth or does not fit the male-female binary). Dr. Lipson is particularly interested in mental health disparities among college students, which include ~70% of adolescents and young adults nationwide. Though TGNC students represent just 3-4% of all undergraduates, they account for ~15% of reported suicide attempts. The proposed K01 focuses on how exposure to structural stigma, in the form of 6 campus policies, is associated with suicidality and mental health service utilization among TGNC college students. This K01 includes 3 specific aims, each requiring further training and expert mentorship: Aims 1 and 2 leverage the natural experiment in which students have low/no exposure to campus policies in the pre-period (before arriving in fall of the 1st undergraduate year). In Aim 1, Dr. Lipson will apply her K01 training in causal inference to compare changes suicidal ideation and attempts between TGNC and cisgender students on campuses with and without structural stigma. In Aim 2, Dr. Lipson will analyze a national database of counseling center records to assess how structural stigma is associated with treatment dropout by TGNC and cisgender students. Supported by her K01 training in qualitative research, in Aim 3, Dr. Lipson will conduct interviews with TGNC students and counseling center directors. This formative research will be in accordance with the preparation phase of the Multiphase Optimization Strategy (MOST), a principled framework for optimizing/evaluating interventions. The preparation phase will inform development and evaluation of future interventions to address structural stigma and its underlying mechanisms. With her K01 research and training, Dr. Lipson will have the skills, knowledge, and evidence to lead intervention evaluation and effectively collaborate on intervention teams. At the end of the K01, she will be prepared to proceed with subsequent phases of MOST, for which she will seek R01 funding. As an assistant professor at the Boston University School of Public Health (BUSPH), Dr. Lipson is opportunely positioned to accomplish the proposed research and achieve her overall career objectives. Her mentors from BUSPH, Boston Children's Hospital/Harvard, and Rutgers University bring interdisciplinary expertise in: TGNC health disparities (Dr. Austin), causal inference (Dr. Lin), qualitative research (Dr. Jernigan), intervention development and evaluation (Dr. Stein), and suicide epidemiology (Dr. Gradus). NIH has designated TGNC as a disparity population, yet there remain large gaps in knowledge that undermine development of public health interventions, including evidence to support implementation of protective policies. With regard to TGNC suicidality, NIMH has specifically highlighted a need to consider transition periods that may heighten risk. Beginning college (the focus of Aims 1 and 2) is a significant life transition that coincides with age of onset for many lifetime mental disorders. The proposed research will strengthen the public health impact of NIMH-supported research (Strategic Objective 4) and address a critical barrier by advancing knowledge of how campus structural stigma is associated with TGNC suicidality. This evidence can be used to inform policy change and create more inclusive services to meet the needs of a growing population of TGNC students nationwide.